Total knee arthroplasty typically involves the replacement of a portion of the patella, femur and/or tibia with artificial components. In many surgeries, a proximal portion of the tibia and a distal portion of the femur are resected, prepared by further cutting, shaping, reaming, and/or punching the bone and replaced with artificial components. As used herein, when referring to bones or other body parts, the term “proximal” means closest to the heart and the term “distal” means more distant from the heart.
After preparing the distal surface of the femur and the proximal surface of the tibia, an opening is made into the medullary canal of the femur, and an opening is made into the medullary canal of tibia. Some implant components include an intramedullary (IM) stem, and when these components are used, the interior surface of the medullary canal and the IM tem of the femoral component are usually covered with polymeric cement. The IM stem is inserted into the medullary canal of the femur until the interior surface of the femoral component meets the distal surface of the femur. The IM stem of the tibial component is usually similarly cemented and inserted in the medullary canal of the tibia.
Occasionally, the femoral and tibial components are press fit without the use of cement. The use of cement has advantages and disadvantages. Press fit components rely on bone quality to obtain good fixation. Sometimes, however, it is impossible to obtain good fixation with a press fit component, and sometimes a press fit component will fail early because of failure of successful biological ingrowth. Cement assures good fixation, but may put strain along the component stem. In addition, cement can complicate the removal of a failed component.
Often, due to normal wear over time, the prosthetic knee must be replaced via a procedure known as revision surgery. When the primary cemented prosthetic is removed, the proximal surface of the tibia and the distal surface of the femur typically exhibit cavernous defects. Absent the use of bone graft, the proximal surface of the tibia and the distal surface of the femur must be carefully resected to remove cavernous defects before a replacement knee can be installed.
In addition, a revision surgery typically requires broaching and/or reaming the intramedullary (IM) canals to remove any remaining cement or cavernous defects existing in the canals before a replacement knee can be installed. Removal of the femoral component and preparation of the distal femur is performed using techniques known in the art. According to the state of the art, after the primary prosthetic is removed, the proximal tibia is resected with a cutting guide. The medullary canal is reamed. A proximal resection guide is attached to the reamer, and proximal resection is completed via slots in the guide.
Defects in the tibia, if present, are evaluated. If a tibial implant augment is deemed necessary, the proximal tibia is further prepared by attaching a multi-slotted augment cutting guide to the reamer and resecting the bone through the slot representing the optimum thickness for the augment to be implanted. After resection of the proximal tibia is completed, the tibial plateau is sized by placing and positioning the tibial template that provides the best coverage for that given tibia. The tibial template is pinned in this position. A punch guide is attached to the template and a keel or fin punch is used to provide a keeled or finned opening to accept the implant. The tibia implant has a cross-sectional keel or fin shape corresponding to the opening punched in the tibia that prevents rotation of the implant once it has been inserted into the punched opening.
Removal of the keel or fin punch typically involves the use of a slap hammer. Examples of devices that utilize slap hammers for the removal of punch instruments during knee surgery are disclosed in U.S. Pat. Nos. 5,690,636 and 5,788,701. Use of a slap hammer to remove a punch has certain disadvantages. One disadvantage of using a slap hammer is that the punch is removed in an uncontrolled manner. In addition, attachment and use of the slap hammer during a surgical procedure is relatively time-consuming, considering the relatively short time period to complete the surgical procedure. It would be desirable to provide a device and method that provides for the controlled removal of a punch from a bone during knee surgery.